Your Ad HereMono County is a county located in the U.S. state of California. As of 2016 the population was 13,981. The county seat is Bridgeport.HistoryMono County was formed in 1861. The county is named after Mono Lake which, in 1852, was named for a Native American Paiute tribe, the Kuzedika, that inhabited the Sierra Nevada from north of Mono Lake to Owens Lake.